CVE-2026-11855
CVE-2026-11855 is a high-severity vulnerability with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 0% (22nd percentile)
- Actively exploited: Not listed in CISA KEV
- Published:
- Last modified:
Description
The Simple Membership WordPress plugin before 4.7.5 does not verify the authenticity of Stripe webhook requests when no signing secret is configured, nor escape a value taken from them before outputting it in an administrator notice, allowing unauthenticated attackers to inject arbitrary web scripts that execute in the context of a logged-in administrator.
Frequently asked questions
- What is CVE-2026-11855?
- The Simple Membership WordPress plugin before 4.7.5 does not verify the authenticity of Stripe webhook requests when no signing secret is configured, nor escape a value taken from them before outputting it in an administrator notice, allowing unauthenticated attackers to inject arbitrary web scripts that execute in the context of a logged-in administrator.
- How severe is CVE-2026-11855?
- CVE-2026-11855 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-11855 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-11855?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2026-11855 published?
- CVE-2026-11855 was published on 2026-07-06.